Conventionally, as a fire detector which senses a fire and outputs an alarm signal to a receiver for a fire alert, a smoke detector which senses smoke due to fire and a heat detector which senses heat (temperature) due to fire have been generally known.
However, only with sensing information such as temperature or smoke concentration, it may be difficult to quickly and appropriately address various fire situations such as smoldering fire and ignited fire. To address this, a composite fire sensor has been known which senses a smoke concentration and temperature due to fire and quickly senses a fire by a composite fire determination without causing an erroneous report or report loss.
On the other hand, at the time of a fire, gas such as CO is known to occur. So, a composite fire detector is also considered in which, other than a fire detecting unit for smoke and heat, a gas sensor is provided to the detector to determine a fire by sensing a gas concentration together with a smoke concentration and heat temperature.